2185. Counting Words With a Given Prefix

You are given an array of strings words and a string pref.

Return the number of strings in words that contain pref as a prefix.

A prefix of a string s is any leading contiguous substring of s.

 Example 1:

Input: words = ["pay","attention","practice","attend"], pref = "at"
Output: 2
Explanation: The 2 strings that contain "at" as a prefix are: "attention" and "attend".

Example 2:

Input: words = ["leetcode","win","loops","success"], pref = "code"
Output: 0
Explanation: There are no strings that contain "code" as a prefix.

 Constraints:

• 1 <= words.length <= 100
• 1 <= words[i].length, pref.length <= 100
• words[i] and pref consist of lowercase English letters.

C++

• class Solution {
  public:
      int prefixCount(vector<string>& words, string pref) {
          int ans = 0;
          for (auto& w : words) ans += w.find(pref) == 0;
          return ans;
      }
  };

JAVA

• class Solution {
      public int prefixCount(String[] words, String pref) {
          int ans = 0;
          for (String w : words) {
              if (w.startsWith(pref)) {
                  ++ans;
              }
          }
          return ans;
      }
  }

PYTHON

• class Solution:
      def prefixCount(self, words: list, pref: str) -> int:
          return sum(w.startswith(pref) for w in words)